Tag Archives: ALT instruction

How to use the ALT instruction in Mitsubishi PLC

ALT instruction is alternate output
Assume that Y0 is the indicator light.
LDP X0
ALT Y0
At this time, Y0 is off, and when X0 is pressed, the indicator lights up. Press again to turn off the light, then press it again. It’s as simple as that, it will alternate output. This can also be used as a single button to start the stop program!
Just use it when using the rising edge to achieve the alternation. If X0 does not use the rising edge, it is very likely that the PLC has actually read this switch twice.